Method of quenching singlet and triplet excited states of photodegradable pigments, such as porphyrin compounds, particularly protoporphyrin ix, with conjugated fused tricyclic compounds having electron withdrawing groups, to reduce generation of singlet oxygen

ABSTRACT

A method of quenching excited state energy from a photodegradable pigment that has been excited by absorption of light having a wavelength in the wavelength range of 290-800 nm, comprising reacting a pigment with a conjugated fused tricyclic compound having electron withdrawing groups of Formula (II) or a salt thereof: 
     
       
         
         
             
             
         
       
         
         
           
             wherein:
           A is selected from the group consisting of O, S, C═O, C═S,   
         
           
         
       
    
     
       
         
         
             
             
         
       
         
         
           
             
               
                 B 1 , B 2 , D 1  and D 2  are each independently selected from the group consisting of F, Cl, Br, I, CF 3 , CC13, NR33+, NO2, CN, C(=0)R4, C(═O)OR′, SO2R5, aryl, and —C═CHR6; 
                 each m independently is 0, 1, 2, 3, or 4; 
                 a is 0 or 1; 
                 each R′ is independently selected from the group consisting of LI, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl; 
                 R 2  is selected from the group consisting of H, alkyl, cycloalkyl, alkenyl, alkynyl, and aryl; 
                 each R 3  is independently selected from the group consisting of H and C 1 -C 6  alkyl; 
                 each R 4  is independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl; 
                 each R 5  is independently selected from the group consisting of H, O, OH, NH 2 , and Cl; and 
                 each R 6  is-independently selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No. 13/805,168, filed on Dec. 18, 2012, now U.S. Pat. No. 9,867,800, which is a National Stage Entry of PCT/US12/67519, filed on Dec. 3, 2012, which claims priority to U.S. Provisional Patent Application No. 61/681,916, filed on Aug. 10, 2012, which are incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention is directed to a method of quenching singlet and triplet electronic excited states of photodegradable pigments with conjugated fused tricyclic compounds having electron withdrawing groups. More particularly, it has been found that conjugated fused tricyclic compounds having electron withdrawing groups quench the singlet and triplet excited states of pigments, such as porphyrin compounds, by accepting or donating an electron, thereby returning the pigments back to their ground state to reduce the formation of free radical (singlet state) oxygen and/or other reactive oxygen species and radical compounds that are damaging to skin cells. Porphyrin compounds, for example, reach an excited state when excited by visible radiation at a wavelength in the range of about 290 to about 800 nm, e.g., sunlight, and when the excited porphyrin compound is reacted with a conjugated fused tricyclic compound having electron withdrawing groups, the excited porphyrin compound, and other photolabile pigments, are returned to their ground state before interacting with cellular oxygen, thereby generating substantially less singlet state oxygen, and preventing oxidative stress to skin cells.

BACKGROUND AND PRIOR ART

Endogenous pigments are substances in living matter that absorb visible light. They may also absorb UV radiation. These substances are produced either within tissues and serve a physiological function, or they are by-products of the metabolic process. Endogenous pigments can be classified into non-hematogenous pigments and hematogenous (i.e., blood derived) pigments. Non-hematogenous pigments include, e.g., melanins, flavins, pterins, and urocanic acid. Melanins are derived from tyrosine, and include eumelaninm pheomelanin, and neuromelanin. Flavins are a group of organic compounds based on pteridine, formed by the tricyclic heteronuclear organic ring isoalloxazine. Examples of flavins include riboflavin, flavin mononucleotide, flavoproteins, and flavin adenine dinucleotide. Pterins are heterocyclic compounds composed of a pteridine ring system, with a keto group and an amino group on positions, 4 and 2, respectively. Examples of pterins include pteridine, biopterin, tetrahydrobiopterin, molybdopterin, cyanopterin, tetrahydromethanopterin, and folic acid. Urocanic acid is an intermediate in the catabolism of L-histidine. Hematogenous pigments include, e.g., hemoglobin, bile pigments, and porphyrins. Hemoglobin is a basic, conjugated protein that is responsible for the transportation of oxygen and carbon dioxide within the blood stream. It is composed of protein, globin, and heme-four molecules of heme are attached to each molecule of globin.

Heme B group of hemoglobin complexed to four interior nitrogen atoms Bile pigments are the metabolic products of heme, and include bilirubin (yellow, tetrapyrrolic breakdown product) and biliverdin (green, tetrapyrrolic breakdown product).

Porphyrins are a group of organic compounds, mainly naturally occurring, but also can be exogenous. Porphyrins are heterocyclic macrocycles composed of four modified pyrrole subunits interconnected at their a carbon atoms via methine bridges (═CH—), as shown in Formula (I). Porphyrins are aromatic. That is, they obey Hickel's rule for aromaticity, possessing 4n+2π electrons (n=4 for the shortest cyclic path) delocalized over the macrocycle. Thus, porphyrin macrocycles are highly conjugated systems and typically have very intense absorption bands in the visible region and may be deeply colored. The macrocycle has 26 π electrons in total. The parent porphyrin is porphine, and substituted porphines are called porphyrins. The porphyrin compounds that have their singlet and triplet excited states quenched by the conjugated, fused tricyclic compound having electron withdrawing groups include any porphyrin compound that includes the moiety of Formula (I) (and derivatives and tautomers thereof), as shown in Formula Ia, particularly protoporphyrin IX, Formula Ib.

A porphyrin without a metal-ion in its cavity is a free base. Some iron-containing porphyrins are called hemes, the pigment in red blood cells. As previously discussed, heme is a cofactor of the protein hemoglobin. Heme-containing proteins, or hemoproteins, are found extensively in nature. Hemoglobin and myoglobin are two O₂-binding proteins that contain iron porphyrins. Various cytochromes are also hemoproteins.

The absorption of visible light (at about 400 to about 800 nm and UV of about 290 to about 400 nm) by a porphyrin compound causes the excitation of an electron in the porphyrin molecule from an initially occupied, lower energy orbital to a higher energy, previously unoccupied orbital. The energy of the absorbed photon is used to energize an electron and cause it to “jump” to a higher energy orbital. See Turro, Modern Molecular Photochemistry, 1991. Two excited electronic states derive from the electronic orbital configuration produced by visible light absorption. In one state, the electron spins are paired (antiparallel) and in the other state the electron spins are unpaired (parallel). The state with paired spins has no resultant spin magnetic moment, but the state with unpaired spins possesses a net spin magnetic moment. A state with paired spins remains a single state in the presence of a magnetic field, and is termed a singlet state. A state with unpaired spins interacts with a magnetic field and splits into three quantized states, and is termed a triplet state.

In the electronically excited state, the porphyrin molecule can transfer its excited state energy to oxygen contained in blood and/or skin cells, thereby generating cell-damaging singlet excited state oxygen (hereinafter “singlet oxygen”), or free radical oxygen. To photostabilize the excited state of the porphyrin molecule so that it does not generate cell-toxic singlet oxygen, the excited state of the porphyrin molecule must be returned to the ground state before it transfers its excited state energy to nearby oxygen molecule.

On the other hand, the excited state of porphyrins has also been intentionally harnassed to administer photodynamic therapy (PDT). Protoporphyrin IX (C₃₄H₃₄N₄O₄) is used in PDT, for example, as a treatment for basal cell carcinoma (BCC), which is the most common form of skin cancer in humans. The PDT treatment involves applying a photosensitizer precursor, such as aminolevulinic acid (ALA) to the cancerous cells, waiting a few hours for the ALA to be taken up by the cells and converted to protoporphyrin IX, and then irradiating the cancerous cells with light in the wavelength of about 380 to about 650 nm which excites the protoporphyrin IX to a singlet excited state after which it intersystem crosses to a triplet excited state thereby making it reactive with oxygen, thereby generating cytotoxic singlet oxygen that kills cancerous and pre-cancerous cells.

SUMMARY

In one aspect, the disclosure provides a method of quenching excited state energy from a photodegradable pigment compound that has been excited by exposure to and absorption of light having a wavelength in the wavelength range of about 290 to about 800 nm, comprising reacting the photodegraded pigment in its excited states with a conjugated fused tricyclic compound having electron withdrawing groups of Formula (II) or a salt thereof:

wherein:

-   A is selected from the group consisting of O, S, C═O, C═S,

-   B¹, B², D¹ and D² are each independently selected from the group     consisting of F, Cl, Br, I, CF₃, CCl₃, NR³ ₃ ⁺, NO₂, CN, C(═O)R⁴,     C(═O)OR¹, SO₂R⁵, aryl, and —C═CHR⁶; -   each m independently is 0, 1, 2, 3, or 4; -   n is 0 or 1; -   each R¹ is independently selected from the group consisting of H,     alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl; -   R² is selected from the group consisting of H, alkyl, cycloalkyl,     alkenyl, alkynyl, and aryl; -   each R³ is independently selected from the group consisting of H and     C₁-C₆ alkyl; -   each R⁴ is independently selected from the group consisting of H,     alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl; -   each R⁵ is independently selected from the group consisting of H, O,     OH, NH₂, and Cl; and, -   each R⁶ is independently selected from the group consisting of     alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl.

In another aspect, the disclosure provides a method of suppressing the generation of singlet oxygen and/or other reactive oxygen species or radical compounds by an excited pigment when mammalian-contained pigment is exposed to light, thereby exciting the pigment to an excited state, by quenching the excited state of the pigment compound with a conjugated fused tricyclic compound having electron withdrawing groups of Formula (II) or a salt thereof. Other oxygen species presented from forming include free radical oxygen, superoxide anion, peroxide, hydroxyl radical, and hydroxyl ion.

In yet another aspect, the invention provides a method of protecting skin from oxidative stress caused by the generation of free radical oxygen comprising coating the skin with a pigment excited state quencher capable of accepting or donating an electron from or to a pigment compound in the excited state and returning the excited pigment compound to its ground state, said pigment quencher comprising a conjugated fused tricyclic compound having electron withdrawing groups of Formula (II) or a salt thereof.

In still another aspect, the invention provides a method of protecting healthy cells adjacent to cancerous or pre-cancerous cells undergoing photodynamic therapy comprising applying a composition comprising a pigment excited state quencher compound to said adjacent cells to reduce the generation of free radical oxygen and other reactive oxygen species from said healthy cells while the photodynamic therapy generates free radical oxygen from said cancerous or pre-cancerous cells with a conjugated fused tricyclic compound having electron withdrawing groups of Formula (II) or a salt thereof.

In some exemplary embodiments of any of the above aspects, the pigment compound is a porphyrin compound comprising a porphyrin moiety of Formula (I) or a derivative or tautomer thereof:

In another aspect, the invention provides a cosmetic or dermatological composition for coating a skin surface to protect the skin from getting damaging amounts of singlet oxygen when skin cell-contained or blood-contained porphyrin compounds are exposed to sunlight, or other visible light comprising a compound of Formula IIb, IIe, IId, IIe, IIf, IIg, IIh, Iii, IIj, Ilk, IIl, IIm, IIn, or a combination thereof:

wherein:

-   each R′ is independently selected from the group consisting of H,     alkyl. alkenyl. alkynyl, cycloalkyl, cycloalkenyl, and aryl; and, -   R² is selected from the group consisting of H, alkyl, cycloalkyl,     alkenyl, alkynyl, and aryl.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates an absorption spectra of the compound of Formula IIai according to a specific example embodiment of the disclosure;

FIG. 1B illustrates an absorption spectra of alkoxy crylene in acetonitrile according to a specific example embodiment of the disclosure;

FIG. 1C illustrates an absorption spectra of Formula IIbi in acetonitrile according to a specific example embodiment of the disclosure;

FIG. 1D illustrates an absorption spectra of Formula IIci in acetonitrile according to a specific example embodiment of the disclosure;

FIG. 1E illustrates an absorption spectra of Formula IIfi in acetonitrile according to a specific example embodiment of the disclosure;

FIG. 1F illustrates an absorption spectra of Formula IIdi/IIei in acetonitrile according to a specific example embodiment of the disclosure;

FIG. 2A illustrates an absorption spectrum of protoporphyrin IX in acetonitrile according to a specific example embodiment of the disclosure;

FIG. 2B illustrates an fluorescence spectrum of protoporphyrin IX in acetonitrile according to a specific example embodiment of the disclosure;

FIG. 3A illustrates fluorescence decay traces monitored at 690 nm using time correlated single photon counting of the compound of Formula IIai in acetonitrile solutions in the absence and presence of different amounts of stabilizers according to a specific example embodiment of the disclosure;

FIG. 3B illustrates fluorescence decay traces monitored at 690 nm using time correlated single photon counting of alkoxy crylene in acetonitrile solutions in the absence and presence of different amounts of stabilizers according to a specific example embodiment of the disclosure;

FIG. 4A is a graph showing inverse fluorescence lifetime vs. acceptor concentration used for determining kq, the bimolecular rate constant for quenching of protoporphyrin IX fluorescence by the compounds of Formula IIai and alkoxy crylene, according to a specific example embodiment of the disclosure, using the experimental data shown in FIGS. 3A and 3B according to a specific example embodiment of the disclosure;

FIG. 4B is a graph showing inverse fluorescence lifetime vs. acceptor concentration used for determining kq, the bimolecular rate constant for quenching of protoporphyrin IX fluorescence by the compounds of Formula IIci, Formula IIbi, Formula IIfi, and a mixture of Formula IIdi and IIei, according to a specific example embodiment of the disclosure;

FIG. 5A illustrates a transient absorption spectrum of an argon saturated acetonitrile solution of protoporphyrin IX, according to a specific example embodiment of the disclosure, recorded 0.1 to 1.5 μs after pulsed laser excitation (355 nm, 5 ns pulse width) according to a specific example embodiment of the disclosure;

FIG. 5B illustrates a transient absorption spectrum of an argon saturated acetonitrile solution of protoporphyrin IX, according to a specific example embodiment of the disclosure, recorded 0.1 to 1.5 μs after pulsed laser excitation (440 nm, 5 ns pulse width) according to a specific example embodiment of the disclosure;

FIG. 5C illustrates a transient absorption spectrum of an argon saturated acetonitrile solution of protoporphyrin IX, according to a specific example embodiment of 25 the disclosure, recorded 0.1 to 1.5 μs after pulsed laser excitation (400 nm, 5 ns pulse width) according to a specific example embodiment of the disclosure;

FIG. 6A is a graph showing inverse triplet state lifetime (measured at 440 nm by laser flash photolysis) vs. acceptor concentration used for determining kq, the bimolecular rate constant for quenching of protoporphyrin IX triplet states by the compounds of Formula IIai and alkoxy crylene according to a specific example embodiment of the disclosure;

FIG. 6B is a graph showing inverse triplet state lifetime (measured at 440 nm by laser flash photolysis) vs. acceptor concentration used for determining kq, the bimolecular rate constant for quenching of protoporphyrin IX triplet states by the compound of Formula IIci according to a specific example embodiment of the disclosure;

FIG. 6C is a graph showing inverse triplet state lifetime (measured at 440 nm by laser flash photolysis) vs. acceptor concentration used for determining kq, the bimolecular rate constant for quenching of protoporphyrin IX triplet states by the compound of Formula IIbi and a mixture of Formula IIdi and IIei according to a specific example embodiment of the disclosure;

FIG. 6D is a graph showing inverse triplet state lifetime (measured at 440 nm by laser flash photolysis) vs. acceptor concentration used for determining kq, the bimolecular rate constant for quenching of protoporphyrin IX triplet states by the compound of Formula IIfi according to a specific example embodiment of the disclosure;

FIG. 7A illustrates an absorption spectrum of the compound of Formula IIai in ethanol solution at 77K according to a specific example embodiment of the disclosure;

FIG. 7B illustrates a luminescence excitation spectrum of the compound of Formula IIai in ethanol solution at 77K according to a specific example embodiment of the disclosure;

FIG. 7C illustrates a luminescence emission spectrum of the compound of Formula IIai in ethanol solution at 77K according to a specific example embodiment of the disclosure;

FIG. 8A illustrates a singlet oxygen phosphorescence spectrum generated by photoexcitation (532 nm) of tetrapenylporphyrin in air saturated CC1₄ solutions using steadystate lamp excitation according to a specific example embodiment of the disclosure;

FIG. 8B illustrates a decay trace generated by photoexcitation (532 nm) of tetrapenylporphyrin in air saturated CC1₄ solutions using pulsed laser excitation, according to a specific example embodiment of the disclosure;

FIG. 9A illustrates inverse phosphorescence lifetime vs. absorption molecule concentration used to determine singlet oxygen quenching rate constants kq for Formula IIai according to a specific example embodiment of the disclosure;

FIG. 9B illustrates inverse phosphorescence lifetime vs. absorption molecule concentration used to determine singlet oxygen quenching rate constants kq for alkoxy crylene according to a specific example embodiment of the disclosure;

FIG. 10 illustrates singlet oxygen phosphorescence decay traces generated by pulsed laser excitation (355 nm) of protoporphyrin IX in air saturated DMSO-d6 solutions in the absence and presence of the compound of Formula IIai according to a specific example embodiment of the disclosure;

FIG. 11 illustrates singlet oxygen phosphorescence decay traces generated by pulsed laser excitation (355 nm) of protoporphyrin IX in air saturated DMSO-d6 solutions in the absence and presence of the alkoxy crylene compound at different concentrations, according to a specific example embodiment of the disclosure;

FIG. 12A illustrates singlet oxygen phosphorescence spectra generated by photoexcitation of Formula IIai and alkoxy crylene at 355 nm in benzophenone in air saturated CC1₄ solution according to a specific example embodiment of the disclosure;

FIG. 12B illustrates and enlargement of the lower portion of FIG. 12A according to a specific example embodiment of the disclosure;

FIG. 13 illustrates an absorption spectrum and a singlet oxygen phosphorescence excitation spectrum (monitored at 1270 nm) of alkoxy crylene in air saturated CC4 solutions according to a specific example embodiment of the disclosure;

FIG. 14A illustrates singlet oxygen phosphorescence decay traces of protoporphyrin IX (25 μM) in air saturated DMSO-d6 solutions in the absence and presence of the compound of Formula IIai monitored at 1270 nm generated by pulsed laser excitation at 355 nm according to a specific example embodiment of the disclosure;

FIG. 14B illustrates singlet oxygen phosphorescence decay traces of protoporphyrin IX (25 μM) in air saturated DMSO-d6 solutions in the absence and presence of the compound of Formula IIai monitored at 1270 nm generated by pulsed laser excitation at 532 nm according to a specific example embodiment of the disclosure;

FIG. 14C illustrates singlet oxygen phosphorescence decay traces of protoporphyrin IX (25 μM) in air saturated DMSO-d6 solutions in the absence and presence of an alkoxy crylene compound monitored at 1270 nm generated by pulsed laser excitation at 355 nm according to a specific example embodiment of the disclosure;

FIG. 14D illustrates singlet oxygen phosphorescence decay traces of protoporphyrin IX (25 μM) in air saturated DMSO-d6 solutions in the absence and presence 30 of an alkoxy crylene compound monitored at 1270 nm generated by pulsed laser excitation at 532 nm according to a specific example embodiment of the disclosure;

FIG. 15 illustrates the structures of protoporphyrin IX and protoporphyrin IX dimethyl ester according to a specific example embodiment of the disclosure.

FIG. 16A illustrates singlet oxygen phosphorescence decay traces of protoporphyrin IX dimethyl ester (25 μM) in air saturated CDCl₃ solutions in the absence and presence of the compound of Formula IIai monitored at 1270 nm generated by pulsed laser excitation at 355 nm according to a specific example embodiment of the disclosure;

FIG. 16B illustrates singlet oxygen phosphorescence decay traces of protoporphyrin IX dimethyl ester (25 μM) in air saturated CDCl₃ solutions in the absence and presence of the compound of Formula IIai, according to a specific example embodiment of the disclosure, monitored at 1270 nm generated by pulsed laser excitation at 532 nm;

FIG. 16C illustrates singlet oxygen phosphorescence decay traces of protoporphyrin IX dimethyl ester (25 μM) in air saturated CDCl₃ solutions in the absence and presence of an alkoxy crylene compound, according to a specific example embodiment of the disclosure, monitored at 1270 nm generated by pulsed laser excitation at 355 nm;

FIG. 16D illustrates singlet oxygen phosphorescence decay traces of protoporphyrin IX dimethyl ester (25 μM) in air saturated CDCl₃ solutions in the absence and presence of an alkoxy crylene compound, according to a specific example embodiment of the disclosure, monitored at 1270 nm generated by pulsed laser excitation at 532 nm;

FIG. 16E illustrates singlet oxygen phosphorescence decay traces of protoporphyrin IX dimethyl ester (25 μM) in air saturated CDCl₃ solutions in the absence and presence of Formula IIci according to a specific example embodiment of the disclosure;

FIG. 16F illustrates singlet oxygen phosphorescence decay traces of protoporphyrin IX dimethyl ester (25 μM) in air saturated CDCl₃ solutions in the absence and presence of Formula IIdi and IIei according to a specific example embodiment of the disclosure;

FIG. 16G illustrates singlet oxygen phosphorescence decay traces of protoporphyrin IX dimethyl ester (25 μM) in air saturated CDCl₃ solutions in the absence and presence of Formula IIbi according to a specific example embodiment of the disclosure;

FIG. 16H illustrates singlet oxygen phosphorescence decay traces of protoporphyrin IX dimethyl ester (25 μM) in air saturated CDCl₃ solutions in the absence and presence of Formula IIfi according to a specific example embodiment of the disclosure;

FIG. 16I illustrates singlet oxygen phosphorescence decay traces of protoporphyrin IX dimethyl ester (25 μM) in air saturated CDCl₃ solutions in the absence and presence of Formula IIai according to a specific example embodiment of the disclosure;

FIG. 16J illustrates singlet oxygen phosphorescence decay traces of protoporphyrin IX dimethyl ester (25 μM) in air saturated CDCl₃ solutions in the absence and presence of alkoxy crylene according to a specific example embodiment of the disclosure;

FIG. 17A illustrates a Stern-Volmer plot of singlet oxygen phosphorescence data from decay traces of protoporphyrin IX (25 μM) in air saturated DMSO-d6 solutions in the absence and presence of the compound of Formula IIai and alkoxy crylene, according to a specific example embodiment of the disclosure, monitored at 1270 nm generated by pulsed laser excitation at 355 nm;

FIG. 17B illustrates a Stern-Volmer plot of singlet oxygen phosphorescence data from decay traces of protoporphyrin IX (25 μM) in air saturated DMSO-d6 solutions in the absence and presence of the compound of Formula IIci, according to a specific example embodiment of the disclosure, monitored at 1270 nm generated by pulsed laser excitation at 532 nm;

FIG. 17C illustrates a Stern-Volmer plot of singlet oxygen phosphorescence data from decay traces of protoporphyrin IX (25 μM) in air saturated DMSO-d6 solutions in the absence and presence of the compound of Formula IIai, IIbi, IIdi, IIfi, and alkoxy crylene, according to a specific example embodiment of the disclosure, monitored at 1270 nm generated by pulsed laser excitation at 355 nm;

FIG. 18A illustrates the structure of Formula IIci according to a specific example embodiment;

FIG. 18B illustrates the structure of Formula IIdi according to a specific example embodiment;

FIG. 18C illustrates the structure of Formula IIei according to a specific example embodiment;

FIG. 19A illustrates a redox potential of protoporphyrin IX according to a specific example embodiment;

FIG. 19B illustrates a redox potential of Formula IIai according to a specific example embodiment;

FIG. 19C illustrates a redox potential of Formula IIbi according to a specific example embodiment;

FIG. 19D illustrates a redox potential of Formula IIfi according to a specific example embodiment;

FIG. 19E illustrates a redox potential of Formula IIci according to a specific example embodiment;

FIG. 19F illustrates a redox potential of a mixture of Formulas IIdi and IIei according to a specific example embodiment; and

FIG. 19G illustrates a redox potential of alkoxy crylene according to a specific example embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Quite surprisingly, it has been found that conjugated fused tricyclic compounds having electron withdrawing groups will quench electronically excited pigments, such as porphyrin molecules, caused when the pigment (e.g., a porphyrin) is excited by absorption of visible light. As a result, the excited state of photodegradable pigments, such as porphyrin molecules, particularly protoporphyrin IX, is returned to the ground state, thereby reducing the generation of singlet oxygen and protecting mammalian skin from oxidative stress, which would otherwise develop from sunlight-induced production of singlet state oxygen. Accordingly, by applying one or more of the conjugated fused tricyclic compounds having electron withdrawing groups, in a dermatologically or cosmetically acceptable carrier, onto mammalian skin, e.g., human skin, the skin will not suffer from oxidative stress due to the generation of potentially cytotoxic singlet oxygen and other reactive oxygen species. Thus, the compositions and methods described herein advantageously quench the excited state reached by pigments, such as porphyrins, particularly protoporphyrin IX, thereby significantly reducing the generation of singlet oxygen and other reactive oxygen species in cells, and thereby preventing oxidative stress.

Ranges may be expressed herein as from “about” or “approximately” one particular value and/or to “about” or “approximately” another particular value. ‘When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment.

Definitions

The term “alkyl” refers to straight chained and branched saturated hydrocarbon groups containing one to thirty carbon atoms, for example, one to thirty carbon atoms, one to twenty carbon atoms, and/or one to ten carbon atoms: The term C_(n) means the alkyl group has “n” carbon atoms. For example, C₄ alkyl refers to an alkyl group that has 4 carbon atoms. C₁-C₇ alkyl refers. to an alkyl groups having a number of carbon atoms encompassing the entire range (i.e., 1 to 7 carbon atoms), as well as all subgroups (e.g., 1-6, 2-7, 1-5, 3-6, 1, 2, 3, 4, 5, 6, and 7 carbon atoms). Nonlimiting examples of alkyl groups include, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl (2-methylpropyl), t-butyl (1,1-dimethylethyl), 3,3-dimethylpentyl, and 2-ethylhexyl Unless. otherwise indicated, an alkyl group can be an unsubstituted alkyl group or a substituted alkyl group. When the term “alkyl” is in parenthesis (e.g., (alkyl)acrylate), then the alkyl group is optional

The term “alkenyl” is defined identically as “alkyl” except for containing at least one carbon..carbon double bond, e.g., ethenyl, 1-propenyl, 2-propenyl, and butenyl. Unless otherwise indicated, an alkenyl group can be an unsubstituted alkenyl group or a substituted alkenyl group.

The term “alkynyl” is defined identically as “alkyl” except for containing at least one carbon-carbon triple bond, e.g., ethynyl, 1-propynyl, 2-propynyl, and butynyl. Unless otherwise indicated, an alkynyl group can be an unsubstituted alkynyl group or a substituted alkynyl group.

The term “cycloalkyl” as used herein refers to an aliphatic cyclic hydrocarbon group containing three to eight carbon atoms. (e.g., 3, 4, 5, 6, 7, or 8 carbon atoms). The term C_(n), means the cycloalkyl group has “n” carbon atoms. For example, C₅ cycloalkyl refers to a cycloalkyl group that has 5 carbon atoms in the ring. C₅-C₈ cycloalkyl refers to cycloalkyl groups having a number of carbon atoms encompassing the entire range. (i.e., 5 to 8 carbon atoms), as well as all subgroups (e.g., 5-6, 6-8, 7-8, 5-7, 5, 6, 7, and 8 carbon atoms). Nonlimiting examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. Unless otherwise indicated, a cycloalkyl group can be an unsubstituted cycloalkyl group or a substituted cycloalkyl group.

The term “heterocycloalkyl” is defined similarly as cycloalkyl, except the ring contains one to three heteroatoms independently selected from the group consisting of oxygen, nitrogen, and sulfur. Nonlimiting examples of heterocycloalkyl groups include piperdine, tetrahydrofuran, tetrahydropyran, dihydrofuran, morpholine, thiophene, and the like. Cycloalkyl and heterocycloalkyl groups can be saturated or partially unsaturated ring systems optionally substituted with, for example, one to three groups, independently selected from the group consisting of alkyl, alkyleneOH, C(O)NH₂, NH₂, oxo (═O), aryl, haloalkyl, halo, and OH. Heterocycloalkyl groups optionally can be further N-substituted with alkyl, hydroxyalkyl, alkylenearyl, or alkyleneheteroaryl.

The term “cycloalkenyl” is defined identically as “cycloalkyl” except for containing at least one double bond, e.g., cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, and cyclooctenyl. Unless otherwise indicated, a cycloalkenyl group can be an unsubstituted cycloalkenyl group or a substituted cycloalkenyl group.

The term “aryl” as used herein refers to monocyclic or polycyclic (e.g., fused bicyclic and fused tricyclic) carbocyclic aromatic ring systems. Examples of aryl groups include, but are not limited to, phenyl, naphthyl, tetrahydronaphthyl, phenanthrenyl, biphenylenyl, indanyl, indenyl, anthracenyl, and fluorenyl. Unless otherwise indicated, an aryl group can be an unsubstituted aryl group or a substituted aryl group.

The term “heteroaryl” as used herein refers to monocyclic or polycyclic (e.g., fused bicyclic and fused tricyclic) aromatic ring systems, wherein one to four-ring atoms are selected from the group consisting of oxygen, nitrogen, and sulfur, and the remaining ring atoms are carbon, said ring system being joined to the remainder of the molecule by any of the ring atoms. Nonlimiting examples of heteroaryl groups include, but are not limited to, pyridyl, pyrazinyl, pyrimidinyl, pyrrolyl, pyrazolyl, imidazolyl, thiazolyl, tetrazolyl, oxazolyl, isooxazolyl, thiadiazolyl, oxadiazolyl, furanyl, quinolinyl, isoquinolinyl, benzoxazolyl, benzimidazolyl, and benzothiazolyl Unless otherwise indicated, a heteroaryl group can be an unsubstituted heteroaryl group or a substituted heteroaryl group.

The term “hydroxy” or “hydroxyl” as used herein refers to an “—OH” group.

The term “alkoxy” or “alkoxyl” as used herein refers to an “—O-alkyl” group.

The term “ester” as used herein refers to a group of the general Formula:

wherein R is an alkyl group or a cycloalkyl group.

The term “ether” as used herein refers to a C₁-C₃₀ alkyl group that includes at least one oxygen atom inserted within the alkyl group.

The term “amino” as used herein refers a —NH₂ or —NH— group, wherein each hydrogen in each Formula can be replaced with. an alkyl, cycloalkyl, aryl, heteroaryl, or heterocycloalkyl group.

The term “carboxy” or “carboxyl” as used herein refers to a “—COOH” group.

The term “carboxylic ester” as used herein refers to a “—(C═O)O-alkyl” group.

The term “sulfhydryl” as used herein refers to a “—SH” group.

The term “halo” as used herein refers to a halogen (e.g., F, Cl, Br, or I).

The term “cyano” as used herein refers to a —C≡N group, also designated —CN.

A “substituted” alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, alkoxyl, ester, ether, or carboxylic ester refers to an alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, alkoxyl, ester, ether, or carboxylic ester having at least one hydrogen radical that is substituted with a non-hydrogen radical (i.e., a substituent). Examples of non-hydrogen radicals (or substituents) include, but are not limited to, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, ether, aryl, heteroaryl, heterocycloalkyl, heterocycloalkyl, hydroxyl, oxy (or oxo), alkoxyl, ester, thioester, acyl, carboxyl, cyano, nitro, amino, amido, sulfur, and halo. When a substituted alkyl group includes more than one non-hydrogen radical, the substituents can be bound to the same carbon or two or more different carbon atoms.

The term “hydroxyalkyl” as used herein refers to an alkyl group that is substituted with a hydroxyl group.

The term “carboxyalkyl” as used herein refers to an alkyl group that is substituted with a carboxyl group.

The term “esteralkyl” as used herein refers to an alkyl group that is substituted with an ester group.

The term “sulfuydrylalkyl” as used herein refers to an alkyl group that is substituted with a sulfhydryl group.

The term “photogenerated reactive oxygen” as used herein refers to singlet oxygen or free radical oxygen, superoxide anion, peroxide, hydroxyl radical, hydroxyl ion, and other reactive oxygen species that are generated when a photodegradable pigment is excited by light having a wavelength of 290 nm to 800 nm.

EMBODIMENTS

The conjugated fused tricyclic compounds having electron withdrawing groups capable of quenching the excited state energy of pigments, such as the porphyrins compounds of Formulae (I) and Ia, are the compounds of Formula (II) or a salt thereof:

Conjugated Fused Tricyclic Compounds Having Electron Withdrawing Groups

wherein: A is selected from the group consisting of O, S, C═O, C═S,

B¹, B², D¹ and D² are each independently selected from the group consisting of F, Cl, Br, I, CF₃, CCl₃, NR³ ₃+, NO₂, CN, C(═O)R⁴, C(═O)OR¹, SO₂R⁵, aryl, and —C═CHR⁶; each m independently is 0, 1, 2, 3, or 4; n is 0 or 1; each R¹ is independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl; R² is selected from the group consisting of H, alkyl, cycloalkyl, alkenyl, alkynyl, and aryl; each R³ is independently selected from the group consisting of H and C₁-C₆ alkyl; each R⁴ is independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl; each R⁵ is independently selected from the group consisting of H, O—, OH, NH₂ and Cl; and, each R⁶ is independently selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl.

In some embodiments:

B¹ and B² are each independently selected from the group consisting of CF₃, CCl₃, NR³ ₃+, NO₂, CN, C(═O)R⁴, C(═O)OR¹, SO₂R⁵, aryl, and —C═CHR⁶; D¹ and D² are each independently selected from the group consisting of F, Cl, Br, I, CF₃, CCl₃, NR³ ₃+, NO₂, CN, C(═O)R⁴, C(═O)OR¹, SO₂R⁵, aryl, and —C═CHR⁶; each m independently is 0, 1, or 2; n is 0 or 1; each R¹ is independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, and aryl; R² is selected from the group consisting of H, alkyl, cycloalkyl. alkenyl, alkynyl, and aryl; each R³ is independently selected from the group consisting of H and C₁-C₆ alkyl; each R⁴ is independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, and aryl; each R⁵ is independently selected from the group consisting of H, O, OH, NH₂, and Cl; and, each R⁶ is independently selected from the group consisting of alkyl, alkenyl, alkynyl, and aryl.

In some embodiments:

B¹ and B² are each independently selected from the group consisting of CN, C(═O)R⁴, C(═O)R¹, SO₂R⁵; D¹ and D² are each independently selected from the group consisting of F, Cl, Br, CF₃, CCl₃, NR³ ₃+, NO₂, CN, C(═O)R⁴, C(═O)OR¹, and SO₂R⁵; each m independently is 0, 1, or 2; n is 0 or 1; each R¹ is independently selected from the group consisting of H, C₁-C₂₀ alkyl, C₁-C₂₀ alkenyl, C₁-C₂₀ alkynyl, and aryl; R² is selected from the group consisting of H, alkyl, cycloalkyl, alkenyl, alkynyl, and aryl; each R³ is independently selected from the group consisting of H and C₁-C₄ alkyl; each R⁴ is independently selected from the group consisting of H, C₁-C₂₀ alkyl, C₁-C₂₀ alkenyl, C₁-C₂₀ allkynyl, and aryl; and, each R⁵ is independently selected from the group consisting of H, O, OH, NH₂, and Cl.

In some of these embodiments, both B¹ and B² are CN, both B¹ and B² are C(═O)OR¹, one of B¹ and B² is CN and the other is C(═O)OR¹, wherein each R¹ is independently selected from the group consisting of H, C₁-C₁₀ alkyl C₁-C₁₀ alkenyl, C₁-C₁₀ alkynyl, and aryl.

In some embodiments where R¹, R², and/or R⁴ is alkenyl, then the double bond can be internal or terminal. In some exemplary embodiments, the double bond is terminal. For example, R¹, R², and/or R⁴ can be, e.g.,

wherein o is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20. In some embodiments o is 9.

In some embodiments where one of B¹ and B² is CN and the other is C(═O)OR¹, the compounds of Formula (II) include the compounds of Formula IIa, IIb, IIc, IId, IIe, IIf, and IIg:

and mixtures thereof.

In some of these embodiments, R¹ is H, C₁-C₃₀ alkyl, C₁-C₂₀ alkyl, or C₁-C₁₀ alkyl. In some exemplary embodiments, R¹ can include H, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, or decyl. For example, R¹ can include, but is not limited to, H, methyl, ethyl, propyl isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, or 2-ethyhexyl.

In some of these embodiments, R² is H, C₁-C₃₀ alkyl, C₁-C₂₀ alkyl, or C₁-C₁₀ alkyl. In some exemplary embodiments, R² can include methyl, ethyl, propyl butyl, pentyl, hexyl, heptyl, octyl, nonyl, or decyl. For example, R² can include, but is not limited to, H, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, or 2-ethylhexyl.

In some exemplary embodiments where one of B¹ and B² is CN and the other is C(═O)OR¹, the compound of Formula (II) is selected from the group consisting of:

and mixtures thereof.

In some embodiments where both of B¹ and B² are C(═O)OR¹, the compounds of Formula (II) include the compounds of Formula IIh, IIi, IIi, IIk, IIl, IIm, and IIn:

and mixtures thereof.

In some of these embodiments, R¹ is H, C₁-C₃₀ alkyl, C₁-C₂₀ alkyl, or C₁-C₁₀ alkyl. In some exemplary embodiments, R¹ can include H, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, or decyl. For example, R¹ can include, but is not limited to, H, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, or 2-ethylhexyl.

In some of these embodiments, R² is H, C₁-C₃₀ alkyl, C₁-C₂₀ alkyl, or C₁-C₀ alkyl. In some exemplary embodiments, R² can include H, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, or decyl. For example, R² can include, but is not limited to, H, methyl, ethyl, propyl, isopropyl, or 2-ethylhexyl.

In some exemplary embodiments where both of B¹ and B² are C(═O)OR¹, the compound of Formula (II) is selected from the group consisting of:

and mixtures thereof.

The photodegradable pigments described herein can include exogenous pigments, such as exogenous porphyrin compounds, or endogenous pigments, such as non-hematogenous pigments, hematogenous (i.e., blood derived) pigments, or mixtures thereof.

In some embodiments, the endogenous photodegradable pigment is a non-hematogenous pigment, such as, for example, melanins, flavins, pterins, urocanic acid.

In some of these embodiments, the photodegradable non-hematogenous pigment is a melanin, such as; for example, eumelanin, pheomelanin, neuromelanin, or mixtures thereof.

In some of these embodiments, the photodegradable non-hematogenous pigment is a flavin, such as, for example, riboflavin, flavin mononucleotide, a flavoprotein, flavin adenine dinucleotide.

In some of these embodiments, the photodegradable non-hematogenous pigment is a pterin, such as, for example, pteridine, biopterin, tetrahydrobiopterin, molybdopterin, cyanopterin, tetrahydromethanopterin, folic acid, and combinations thereof.

In some of these embodiments, the photodegradable non-hematogenous pigment is urocanic acid.

In some embodiments, the photodegradable endogenous pigment is a hematogenous pigment. The hematogenous pigment can include, for example, hemoglobin, bile pigments, porphyrins, and mixtures thereof.

In some embodiments, the photodegradable hematogenous pigment is hemoglobin.

In some embodiments, the photodegradable hematogenous pigment is a bile pigment. In some embodiments, the bile pigment is bilirubin, biliverdin, or a mixture thereof.

In some embodiments, the photodegradable hematogenous pigment is a porphyrin. In other embodiments, the pigment is an exogenous porphyrin. The porphyrin compounds described herein include a porphyrin moiety of Formula (I) or a derivative or tautomer thereof:

In some embodiments, the porphyrin moiety of Formula Ia is:

or a multimer thereof, wherein:

R^(7a), R^(7b), R^(7c), R^(7d), R^(7e), R^(7f), R^(7g), R^(7h) are each independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, hydroxyl, alkoxyl, carboxyl, carboxylic ester, amino, sulfhydryl, aryl, and heteroaryl; and,

R^(8a), R^(8b), R^(8d), and R^(8e) are each independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, hydroxyl, alkoxyl, carboxyl, carboxylic ester, amino, sulfhydryl, aryl and heteroaryl.

In some embodiments, R^(7a), R^(7b), R^(7c), R^(7d), R^(7e), R^(7f), R^(7g), R^(7h) are each independently selected from the group consisting of H, C₁-C₆ unsubstituted alkyl, C₁-C₆ hydroxyalkyl, C₁-C₆ carboxyalkyl, C₁-C₆ esteralkyl, C₁-C₆ sulfhydrylalkyl C₁-C₆ alkenyl, amino, aryl, and heteroaryl.

In some exemplary embodiments, R^(7a), R^(7b), R^(7c), R^(7d), R^(7e), R^(7f), R^(7g), R^(7h) are each independently selected from the group consisting of H, C₁-C₄ unsubstituted alkyl, C₁-C₄ hydroxyalkyl, C₁-C₄ carboxyalkyl, C₁-C₄ esteralkyl, C₁-C₆ sulfhydrylalkyl, C₁-C₄ alkenyl, aryl, and heteroaryl. For example, R^(7a), R^(7b), R^(7c), R^(7d), R^(7e), R^(7f), R^(7g), R^(7h) can each independently be selected from the group consisting of H, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, iso-butyl, tert-butyl, ethenyl, 1-propenyl, 2-propenyl, 1-hydroxyethyl, 2-hydroxyethyl, phenyl, acetic acid, methyl acetate, ethyl acetate, propionic acid, methyl propanate, ethylpropanate, and

In some embodiments, R^(8a), R^(8b), R^(8c), R^(8d), and R^(8e) are each independently selected from the group consisting of H, C₁-C₆ alkyl, C₁-C₆ alkenyl, aryl, and heteroaryl. In some exemplary embodiments, R^(8a), R^(8b), R^(8c), R^(8d), and R^(8e) are each independently selected from the group consisting of H, C₁-C₄ alkyl, C₁-C₄ alkenyl, phenyl, naphthyl, and pyridyl. For example, R^(8a), R^(8b), R^(8c), R^(8d), and R^(8e) can each independently be selected from the group consisting of H, phenyl, hyrdroxyphenyl, dihydroxyphenyl, trihydroxyphenyl, methoxyphenyl, dimethoxyphenyl, trimethoxyphenyl, carboxyphenyl, trimethylanilinium, naphthyl, sulfonatophenyl, pyridyl, and N-methyipyridyl.

In some embodiments, R^(7a), R^(7b), R^(7c), R^(7d), R^(7e), R^(7f), R^(7g), R^(7h) are each independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, hydroxyl, alkoxyl, carboxyl, carboxylic ester, amino, sulfhydryl, aryl, and heteroaryl; and R^(8a), R^(8b), R^(8c), R^(8d), and R^(8e) are each independently selected from the group consisting of H, alkyl, alkenyl, alkynyl. hydroxyl, alkoxyl, carboxyl, carboxylic ester, amino, sulfhydryl, aryl, and heteroaryl.

In other embodiments, R^(7a), R^(7b), R^(7c), R^(7d), R^(7e), R^(7f), R^(7g), R^(7h) are each independently selected from the group consisting of H, C₁-C₆ unsubstituted alkyl, C₁-C₆ hydroxyalkyl, C₁-C₆ carboxyalkyl, C₁-C₆ esteralkyl, C₁-C₆ sulfhydrylalkyl C₁-C₆ alkenyl, amino, aryl, and heteroaryl; and R^(8a), R^(8b), R^(8c), R^(8d), and R^(8e) are each independently selected from the group consisting of H, C₁-C₆ alkyl, C₁-C₆ alkenyl, aryl, and heteroaryl.

In yet other embodiments, R^(7a), R^(7b), R^(7c), R^(7d), R^(7e), R^(7f), R^(7g), R^(7h) are each independently selected from the group consisting of H, C₁-C₄ unsubstituted alkyl, C₁-C₄ hydroxyalkyl, C₁-C₄, carboxyalkyl, C₁-C₄ esteralkyl, C₁-C₆ sulfhydrylalkyl, C₁-C₄ alkenyl, aryl, or heteroaryl; and R^(8a), R^(8b), R^(8c), R^(8d), and R^(8e), are each independently selected from the group consisting of H, C₁-C₄ alkyl, C₁-C₄ alkenyl, phenyl, naphthyl, and pyridyl.

In still other embodiments, R^(7a), R^(7b), R^(7c), R^(7d), R^(7e), R^(7f), R^(7g), R^(7h) are each independently selected from the group consisting of H, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, iso-butyl, tert-butyl, ethenyl, 1-propenyl, 2-propenyl, 1-hydroxyethyl, 2-hydroxyethyl, phenyl, acetic acid, methyl acetate, ethyl acetate, propionic acid, methyl propanate, ethylpropanate, and

and R^(8a), R^(8b), R^(8c), R^(8d), and R^(8e) are each independently selected from the group consisting of H, phenyl, hydroxyphenyl, dihydroxyphenyl, trihydroxyphenyl, methoxyphenyl, dimethoxyphenyl, trimethoxyphenyl, carboxyphenyl, trimethylanilinium, naphthyl, sulfonatophenyl, pyridyl, and N-methylpyridyl.

All porphyrin compounds that are excited by visible light are returned to their ground state by the conjugated fused tricyclic compounds having electron withdrawing groups described herein. The porphyrin compounds include, but are not limited to, 5-azaprotoporphyrin IX, bis-porphyrin, coproporphyrin HI, deuteroporphyrin, deuteroporphyrin IX dichloride, diformyl deuteroprophyrin IX, dodecaphenylporphyrin, hematoporphyrin, hematoporphyrin IX, hematoporphyrin monomer, hematoporphyrin dimer, hematoporphyrin derivative, hematoporphyrin derivative A, hematoporphyrin IX dihydrochloride, hematoporphyrin dihydrochloride, mesoporphyrin, mesoporphyrin IX, monohydroxyethylvinyl deuteroporphyrin, 5,10,15,20-tetra(o-hydroxyphenyl)porphyrin, 5,10,15,20-tetra(m-hydroxyphenyl)porphyrin, 5,10,15,20-tetra(p-hydroxyphenyl) porphyrin, 5,10,15,20-tetrakis(3-methoxyphenyl)-porphyrin, 5,10,15,20-tetrakis(3,4-dimethoxyphenyl)porphyrin, 5,10,15,20-.tetrakis (3,5-dimethoxyphenyl) porphyrin, 5,10,15,20-tetrakis(3,4,5-trimethoxyphenyl)porphyrin, 2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetraphenylporphyrin, porphyrin c, protoporphyrin, protoporphyrin IX, tetra-. (4-N-carboxyphenyl)-porphine, tetra-(3-methoxyphenyl)-porphine, tetra-(3-methoxy-2,4-difluorophenyl)-porphine, 5,10,15,20-tetrakis(4-N-methylpyridyl)porphine, tetra-(4-N-methylpyridyl)-porphine tetrachloride, tetra-(3-N-methylpyridyl)-porphine, tetra-(2-N-methylpyridyl)-porphine, tetra(4-N,N,N-trimethylanilinium)porphine, tetra-(4-N,N,N″-trimethylamino-phenyl)porphine tetrachloride, tetranaphthaloporphyrin, tetraphenylporphyrin, tetra-(4-sulfonatophenyl)-porphine, 4-sulfonatophenylporphine, uroporphyrin, uroporphyrin III, uroporphyrin IX, and uroporphyrin I, and esters thereof.

In some embodiments, the porphyrin compound is an ester selected from the group consisting of 5-azaprotoporphyrin dimethylester, coproporphyrin III tetramethylester, deuteroporphyrin IX dimethylester, diformyl deuteroporphyrin IX dimethylester, hematoporphyrin IX dimethylester, mesoporphyrin dimethylester, mesoporphyrin IX dimethylester, monoformyl-monovinyl-deuteroporphyrin IX dimethylester, protoporphyrin dimethylester, and protoporphyrin IX dimethylester.

In some exemplary embodiments, the porphyrin compound is selected from the group consisting of coproporphyrin III, coproporphyrin III tetramethylester, deuteroporphyrin, deuteroporphyrin IX dichloride, deuteroporphyrin IX dimethylester, hematoporphyrin, hematoporphyrin IX, hematoporphyrin derivative, hematoporphyrin derivative A, hematoporphyrin IX dihydrochloride, hematoporphyrin dihydrochloride, hematoporphyrin IX dimethylester, mesoporphyrin, mesoporphyrin dimethylester, mesoporphyrin IX, mesoporphyrin IX dimethylester, protoporphyrin, protoporphyrin IX, protoporphyrin dimethylester, protoporphyrin IX dimethylester, uroporphyrin, uroporphyrin III, uroporphyrin IX, and uroporphyrin I.

For example, the porphyrin compound can include protoporphyrin IX, deuteroporphyrin IX dichloride, deuteroporphyrin IX dimethylester, hematoporphyrin, hematoporphyrin IX, hematoporphyrin derivative, mesoporphyrin dimethylester, mesoporphyrin IX, or mesoporphyrin IX dimethylester.

In some embodiments, the porphyrin compound exists as a free base. In other embodiments, the porphyrin compound is chelated to a metal. In some embodiments, the metal has a 2+ or 3+ oxidation state. In some embodiments, the metal can include, for example, beryllium, magnesium, aluminum, calcium, strontium, barium, radium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium, indium, tin, lead, and platinum.

A particularly useful porphyrin compound is protoporphyrin IX having the structure (Ib):

Thus, one aspect provides a method of quenching excited state energy from an photodegradable pigment compound that has been excited by absorption of light having a wavelength in the wavelength range of about 290 to about 800 nm, comprising reacting the pigment compound with a conjugated fused tricyclic compound having electron withdrawing groups of Formula (II) or a salt thereof:

as previously defined above.

In some exemplary embodiments of this aspect, the photodegradable pigment compound includes a porphyrin compound comprising a porphyrin moiety of Formula (I) or a derivative or tautomer thereof:

as previously defined above.

Another aspect provides a method of suppressing the generation of singlet oxygen by an excited pigment when a mammalian-contained pigment is exposed to light, thereby exciting the pigment to an excited state, by quenching the excited state of the pigment compound with a conjugated fused tricyclic compound having electron withdrawing groups of Formula (II) or a salt thereof:

as previously defined above.

In some exemplary embodiments of this aspect, the pigment compound includes a porphyrin compound comprising a porphyrin moiety of Formula (I) or a derivative or tautomer thereof:

as previously defined above.

Yet another aspect provides a method of protecting skin from oxidative stress caused by the generation of free radical oxygen comprising contacting, preferably coating the skin with an pigment excited state quencher capable of accepting or donating an electron from or to an pigment compound in the excited state and returning the excited pigment compound to its ground state, said pigment quencher comprising a conjugated fused tricyclic compound having electron withdrawing groups of Formula (II) or a salt thereof:

as previously defined above.

In some exemplary embodiments of this aspect, the pigment compound includes a porphyrin compound comprising a porphyrin moiety of Formula (I) or a derivative or tautomer thereof:

as previously defined above.

Still another aspect provides a method of protecting healthy cells adjacent to cancerous or pre-cancerous cells undergoing photodynamic therapy comprising applying a coating composition containing a pigment excited state quencher compound to said adjacent cells to reduce the generation of free radical oxygen and other reactive oxygen species from said healthy cells while the photodynamic therapy generates free radical oxygen from said cancerous or pre-cancerous cells; with a conjugated fused tricyclic compound having electron withdrawing groups of Formula (II) or a salt thereof:

as previously defined above.

In some exemplary embodiments of this aspect, the pigment compound includes a porphyrin compound comprising a porphyrin moiety of Formula (I) or a derivative or tautomer thereof:

as previously defined above.

In accordance with one important embodiment, a conjugated fused tricyclic compound having electron withdrawing groups of Formula (II), IIa, IIb, IIc, IId, IIe, IIf, IIg, IIh, IIi, IIj, IIk, IIl, IIm, IIn, or a combination thereof is included in a cosmetic or dermatological composition for contacting, and preferably coating a skin surface to protect the skin from contacting damaging amounts of singlet oxygen and other reactive oxygen species which, without the presence of the conjugated fused tricyclic compound having electron withdrawing groups, would be generated when skin cell-contained or blood-contained porphyrin compounds, particularly protoporphyrin IX, are exposed to sunlight, or other visible light. In another embodiment, the cosmetic or dermatological composition can also include a UVA filter and/or UVB filter compound and/or a broad-band filter compound for protection of the skin from UVA and/or UVB wavelengths.

The conjugated fused tricyclic compounds having electron withdrawing groups of Formula (II) can be used to suppress the generation of other reactive oxygen species or radical compounds. Some of these reactive oxygen species include, for example, free radical oxygen, superoxide anion, peroxide, hydroxyl radical, and hydroxyl ion. It should be understood that throughout this disclosure whenever singlet state oxygen or free radical oxygen is described as being suppressed, these other oxygen species also may be suppressed.

The conjugated fused tricyclic compound having electron withdrawing groups of Formula (II) can be included in the cosmetic or dermatological composition in an amount of about 0.01% by weight to about 20% by weight, preferably from about 0.1 to about 20% by weight, more preferably from about 0.1% to about 10% by weight, in each case based on the total weight of the composition.

The total amount of one or more water-soluble UV filter substances in the finished cosmetic or dermatological compositions is advantageously chosen from the range of about 0.01% by weight to about 20% by weight, preferably from about 0.1% to about 20% by weight, more preferably from about 0.1% to about 10% by weight, in each case based on the total weight of the composition:

Preferred UV filter compounds, and photostabilizers for the UV filter compounds, are disclosed in published PCT application WO 2009/020676, hereby incorporated by reference for preferred water soluble, organic and particulate UV filter compounds.

In some embodiments, the UV filter compound is a benzotriazle compound having the structure

The cosmetic or dermatological compositions can include an additional photoactive compound. In some embodiments, the additional photoactive compound is selected from the group consisting of p-aminobenzoic acid and salts and derivatives thereof; anthranilate and derivatives thereof; salicylate and derivatives thereof; cinnamic acid and derivatives thereof; dihydroxycinnamic acid and derivatives thereof; camphor and salts and derivatives thereof; trihydroxycinnamic acid and derivatives thereof; dibenzalacetone naptholsulfonate and salts and derivatives thereof; benzalacetophenone naphtholsulfonate and salts and derivatives thereof; dihydroxy-naphthoic acid and salts thereof; o-hydroxydiphenyldisulfonate and salts and derivatives thereof; p-hydroxdydiphenyldisulfonate and salts and derivatives thereof; coumarin and derivatives thereof; diazole derivatives; quinine derivatives and salts thereof; quinoline derivatives; hydroxyl-substituted benzophenone derivatives; naphthalate derivatives; methoxy-substituted benzophenone derivatives; uric acid derivatives; vilouric acid derivatives; tannic acid and derivatives thereof; hydroquinone; benzophenone derivatives; 1, 3, 5-triazine derivatives; phenyldibenzimidazole tetrasulfonate and salts and derivatives thereof; terephthalyidene dicamphor sulfonic acid and salts and derivatives thereof; methylene bis-benzotriazolyl tetramethylbutylphenol and salts and derivatives thereof; bis-ethylhexyloxyphenol methoxyphenyl triazine and salts, diethylamino hydroxyl benzoyl and derivatives thereof; and combinations of the foregoing.

The cosmetic or dermatological composition may include a cinnamate ester, such as 2-ethylhexyl p-methoxycinnamate, isoamyl p-methoxycinnamate, and a combination thereof. For example, the cinnamate ester can be 2-ethylhexyl p-methoxycinnamate. In some of these embodiments, the cinnamate ester is present in the composition in an amount in a range of about 0.1 wt. % to about 15 wt. %, based on the total weight of the composition.

The cosmetic or dermatological composition also may include about 0.1 to about 10 wt. % of a triplet quencher selected from the group consisting of octocrylene, methyl benzylidene camphor, diethylhexyl 2,6-naphthalate, and combinations thereof.

The cosmetic or dermatological composition also may include about 0.1 to about 10 wt. % of a singlet quencher such as an alkoxy crylene (e.g., ethylhexyl methoxy crylene), a copolymer of adipic acid and neopentyl glycol that is terminated with cyanodiphenyl propenoic acid, and mixtures thereof.

The cosmetic or dermatological compositions may have conventional additives and solvents used for the treatment, care and cleansing of skin and/or the hair and as a make-up product in decorative cosmetics.

For use in protecting skin from oxidative stress, the cosmetic and/or dermatological compositions can contain about 0.01 wt. % to about 20 wt. % conjugated fused tricyclic compound(s) having electron withdrawing groups and the composition is applied to the skin and/or the hair in a sufficient quantity in the manner customary for cosmetics.

The cosmetic and dermatological compositions described herein can comprise cosmetic auxiliaries such as those conventionally used in such preparations, e.g. preservatives, bactericides, perfumes, antifoams, dyes, pigments which have a coloring effect, thickeners, moisturizers and/or humectants, fats, oils, waxes or other conventional constituents of a cosmetic or dermatological composition, such as alcohols, polyols, polymers, foam stabilizers, electrolytes, organic solvents or silicone derivatives.

An additional content of antioxidants is generally preferred. According to the invention, favorable antioxidants which can be used are any antioxidants suitable or conventional for cosmetic and/or dermatological applications.

The antioxidants are particularly advantageously chosen from the group consisting of amino acids (e.g. glycine, histidine, tyrosine, tryptophan) and derivatives thereof, imidazoles (e.g. urocanic acid) and derivatives thereof, peptides such as D,L-camosine, D-camosine, L-camosine and derivatives thereof (e.g. anserine), carotenoids, carotenes (e.g. α-carotene, β-carotene, lycopene) and derivatives thereof, chlorogenic acid and derivatives thereof, lipoic acid and derivatives thereof (e.g. dihydrolipoic acid), aurothioglucose, propylthiouracil and other thiols (e.g. thioredoxin, glutathione, cysteine, cystine, cystamine and the glycosyl, N-acetyl, methyl, ethyl, propyl, amyl, butyl and lauryl, palmitoyl, oleyl, .gamma.-linoleyl, cholesteryl and glyceryl esters thereof) and salts thereof, dilauryl thiodipropionate, distearyl thiodipropionate, thiodipropionic acid and derivatives thereof (esters, ethers, peptides, lipids, nucleotides, nucleosides and salts) and sulfoximine compounds (e.g. buthionine sulfoximines, homocysteine sulfoximine, buthionine sulfones, penta-, hexa-, heptathionine sulfoximine) in very low tolerated doses (e.g. pmol to μmol/kg), and also (metal) chelating agents (e.g. α-hydroxy fatty acids, palmitic acid, phytic acid, lactoferrin), α-hydroxy acids (e.g. citric acid, lactic acid, malic acid), humic acid, bile acid, bile extracts, bilirubin, biliverdin, EDTA, EGTA and derivatives thereof, unsaturated fatty acids and derivatives thereof (e.g. gamma.-linolenic acid, linoleic acid, oleic acid), folic acid and derivatives thereof, ubiquinone and ubiquinol and derivatives thereof, vitamin C and derivatives (e.g. ascorbyl palmitate, Mg ascorbyl phosphate, ascorbyl acetate), tocopherols and derivatives (e.g. vitamin E acetate), vitamin A and derivatives (vitamin A palmitate) and coniferyl benzoate of gum benzoin, rutinic acid and derivatives thereof, α-glycosylrutin, ferulic acid, furfurylideneglucitol, carnosine, butylhydroxytoluene, butylhydroxyanisole, nordihydroguaiaretic acid, trihydroxybutyro-phenone, uric acid and derivatives thereof, mannose and derivatives thereof, zinc and derivatives thereof (e.g. ZnO, ZnSO₄), selenium and derivatives thereof (e.g. selenomethionine), stilbenes and derivatives thereof (e.g. stilbene oxide, trans-stilbene oxide) and the derivatives (salts, esters, ethers, sugars, nucleotides, nucleosides, peptides and lipids) of said active ingredients which are suitable according to the invention.

Thus, in some embodiments, the cosmetic or dermatological composition can include one or more oxidation-sensitive or UV-sensitive ingredients selected from the group consisting of retinoid compounds, carotenoid compounds, lipoic acid and derivatives thereof, vitamin E and derivatives thereof, vitamin F and derivatives thereof, and dioic acid in an amount from about 0.0001 wt % to about 10 wt %, based on the total weight of the composition.

Advantageous hydrophilic active ingredients which (individually or in any combinations with one another) are stabilized by their use together with one or more conjugated fused tricyclic compounds having electron withdrawing groups include those listed below: biotin; carnitine and derivatives; creatine and derivatives; folic acid; pyridoxine; niacinamide; polyphenols (in particular flavonoids, very particularly alpha-glucosylrutin); ascorbic acid and derivatives; Hamamelis; Aloe Vera; panthenol; and amino acids.

Particularly advantageous hydrophilic active ingredients for the purposes of the present invention are also water-soluble antioxidants, such as, for example, vitamins.

The amount of hydrophilic active ingredients (one or more compounds) in the compositions is preferably about 0.0001% to about 10% by weight, particularly preferably about 0.001% to about 5% by weight, based on the total weight of the composition.

Particularly advantageous compositions are also obtained when antioxidants are used as additives or active ingredients. According to the invention, the cosmetic or dermatological compositions advantageously comprise one or more antioxidants. Favorable, but nevertheless optional antioxidants which may be used are all antioxidants customary or suitable for cosmetic and/or dermatological applications.

The amount of antioxidants (one or more compounds) in the compositions is preferably about 0.001% to about 30% by weight, particularly preferably about 0.05% to about 20% by weight, in particular about 0.1% to about 10% by weight, based on the total weight of the composition.

If vitamin E and/or derivatives thereof are the antioxidant or antioxidants, it is advantageous to choose their respective concentrations from the range from about 0.001% to about 10% by weight, based on the total weight of the composition.

If vitamin A or vitamin A derivatives, or carotenes or derivatives thereof are the antioxidant or antioxidants, it is advantageous to choose their respective concentrations from the range from about 0.001% to about 10% by weight, based on the total weight of the composition.

It is particularly advantageous when the cosmetic or dermatological compositions, according to the present invention, comprise further cosmetic or dermatological active ingredients, preferred active ingredients being additional antioxidants which can further protect the skin against additional oxidative stress.

Advantageous further active ingredients are natural active ingredients and/or derivatives thereof, such as e.g. ubiquinones, retinoids, carotenoids, creatine, taurine and/or j-alanine.

Compositions according to the invention, which comprise e.g. known antiwrinkle active ingredients, such as flavone glycosides (in particular α-glycosylrutin), coenzyme Q10, vitamin E and/or derivatives and the like, are particularly advantageously suitable for the prophylaxis and treatment of cosmetic or dermatological changes in skin, as arise, for example, during skin aging (such as, for example, dryness, roughness and formation of dryness wrinkles, itching, reduced refatting (e.g. after washing), visible vascular dilations (teleangiectases, couperosis), flaccidity and formation of wrinkles and lines, local hyperpigmentation, hypopigmentation and abnormal pigmentation (e.g. age spots), increased susceptibility to mechanical stress (e.g. cracking) and the like). In addition, they are advantageously suitable against the appearance of dry or rough skin.

The cosmetic or dermatological compositions can include triazines, benzotriazoles, latex particles, organic pigments, inorganic pigments, and mixtures thereof.

Preferred particulate UV filter substances for the purposes of the present invention are inorganic pigments, especially metal oxides and/or other metal compounds which are slightly soluble or insoluble in water, especially oxides of titanium (TiO₂), zinc (ZnO), iron (e.g. Fe₂O₃), zirconium (ZrO₂), silicon (SiO₂), manganese (e.g. MnO), aluminum (Al₂O₃), cerium (e.g. Ce₂O₃), mixed oxides of the corresponding metals, and mixtures of such oxides, and the sulfate of barium (BaSO₄).

Zinc oxides for the purposes of the present invention may also be used in the form of commercially available oily or aqueous predispersions. Zinc oxide particles and predispersions of zinc oxide particles which are suitable according to the invention are distinguished by a primary particle size of <300 nm and can be obtained under the following proprietary names from the stated companies:

Proprietary name Coating Manufacturer Z-Cote HP1 2% Dimethicone BASF Z-Cote / BASF ZnO NDM 5% Dimethicone H&R ZnO Neutral / H&R MZ-300 / Tayca Corporation MZ-500 / Tayca Corporation MZ-700 / Tayca Corporation MZ-303S 3% Dimethicone Tayca Corporation MZ-505S 5% Dimethicone Tayca Corporation MZ-707S 7% Dimethicone Tayca Corporation MZ-303M 3% Dimethicone Tayca Corporation MZ-505M 5% Dimethicone Tayca Corporation MZ-707M 7% Dimethicone Tayca Corporation Z-Sperse Ultra ZnO (>=56%)/Ethylhexyl Collaborative Hydroxystearate Benzoate/ Laboratories Dimethicone/Cyclomethicone Samt-UFZO- ZnO (60%)/ Miyoshi Kasei 450/D5 (60%) Cyclomethicone/Dimethicone

Particularly preferred zinc oxides for the purposes of the invention are Z-Cote HP1 and Z-Cote from BASF and zinc oxide NDM from Haarmann & Reimer.

Titanium dioxide pigments of the invention may be in the form of both the rutile and anatase crystal modification and may for the purposes of the present invention advantageously be surface-treated (“coated”), the intention being for example to form or retain a hydrophilic, amphiphilic or hydrophobic character. This surface treatment may consist of providing the pigments by processes known per se with a thin hydrophilic and/or hydrophobic inorganic and/or organic layer. The various surface coatings may for the purposes of the present invention also contain water.

Inorganic surface coatings for the purposes of the present invention may consist of aluminum oxide (Al₂O₃), aluminum hydroxide Al(OH)₃ or aluminum oxide hydrate (also: alumina, CAS No.: 1333-84-2), sodium hexametaphosphate (NaPO₃)₆, sodium metaphosphate (NaPO₃)_(n), silicon dioxide (SiO₂) (also: silica, CAS No.: 7631-86-9), or iron oxide (Fe₂O₃). These inorganic surface coatings may occur alone, in combination and/or in combination with organic coating materials.

Organic surface coatings for the purposes of the present invention may consist of vegetable or animal aluminum stearate, vegetable or animal stearic acid, lauric acid, dimethylpolysiloxane (also: dimethicones), methylpolysiloxane (methicones), simethicones (a mixture of dimethylpolysiloxane with an average chain length of from about 200 to about 350 dimethylsiloxane units and silica gel) or alginic acid. These organic surface coatings may occur alone, in combination and/or in combination with inorganic coating materials.

Coated and uncoated titanium dioxides may be used in the form of commercially available oily or aqueous predispersions. It may be advantageous to add dispersion aids and/or solubilization mediators.

Suitable titanium dioxide particles and predispersions of titanium dioxide particles for addition to the compositions described herein are obtainable under the following proprietary names from the stated companies:

Additional ingredients of the Proprietary name Coating predispersion Manufacturer MT-150W None — Tayca Corporation MT-150A None — Tayca Corporation MT-500B None — Tayca Corporation MT-600B None — Tayca Corporation MT-100TV Aluminum — Tayca Corporation hydroxide Stearic acid MT-100Z Aluminum — Tayca Corporation hydroxide Stearic acid MT-100T Aluminum — Tayca Corporation hydroxide Stearic acid MT-500T Aluminum — Tayca Corporation hydroxide Stearic acid MT-100S Aluminum — Tayca Corporation hydroxide Lauric acid MT-100F Stearic acid Iron — Tayca Corporation oxide MT-100SA Alumina Silica — Tayca Corporation MT-500SA Alumina Silica — Tayca Corporation MT-600SA Alumina Silica — Tayca Corporation MT-100SAS Alumina Silica — Tayca Corporation Silicone MT-500SAS Alumina Silica — Tayca Corporation Silicone MT-500H Alumina — Tayca Corporation MT-100AQ Silica — Tayca Corporation Aluminum hydroxide Alginic acid Eusolex T Water — Merck KgaA Simethicone Eusolex T-2000 Alumina — Merck KgaA Simethicone Eusolex T-Olio F Silica C₁₂₋₁₅ Merck KgaA Dimethylsilate Alkylbenzoate Water Calcium Poly- hydroxystearate Silica Dimethylsilate Eusolex T-Olio P Water Octyl Palmitate Simethicone PEG-7 Hydrogenated Castor Oil Sorbitan Oleate Hydrogenated Castor Oil Beeswax Stearic acid Eusolex T-Aqua Water Alumina Phenoxyethanol Sodium Sodium metaphosphate Methylparabens Sodium metaphosphate Eusolex T-45D Alumina Isononyl Simethicone Isononanuate Polyglyceryl Ricinoleate Kronos 1171 None — Kronos (Titanium dioxide 171) Titanium dioxide P25 None — Degussa Titanium dioxide Octyltri- — Degussa T805 methylsilane (Uvinul TiO₂) UV-Titan X610 Alumina Kemira Dimethicone UV-Titan X170 Alumina Kemira Dimethicone UV-Titan X161 Alumina Silica Kemira Stearic acid UV-Titan M210 Alumina Kemira UV-Titan M212 Alumina Glycerol Kemira UV-Titan M262 Alumina Kemira Silicone UV-Titan M160 Alumina Silica Kemira Stearic acid Tioveil AQ 10PG Alumina Silica Water Propylene Solaveil Uniquema glycol Mirasun TiW 60 Alumina Silica Water Rhone-Poulenc

Preferred titanium dioxides are distinguished by a primary particle size between about 10 nm to about 150 nm.

Titanium dioxides particularly preferred for the compositions described herein are MT-100 Z and MT-100 TV from Tayca Corporation, Eusolex T-2000 from Merck and titanium dioxide T 805 from Degussa.

Further advantageous pigments are latex particles. Latex particles which are advantageously included in the compositions described herein are described in the following publications: U.S. Pat. No. 5,663,213 and EP 0 761 201. Particularly advantageous latex particles are those formed from water and styrene/acrylate copolymers and available for example under the proprietary name “Alliance SunSphere” from Rohm & Haas.

An advantageous organic pigment for addition to the compositions described herein is 2,2′-methylenebis(6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl-)phenol) (INCI: bis-octyltriazol), which is obtainable under the proprietary name Tinosorb® M from CIBA-Chemikalien GmbH.

EXAMPLES

Initially planned experiments involved the effects of the photoprotecting conjugated fused tricyclic compounds having electron withdrawing groups of Formula (II) and the alkoxy crylene photostabilizer in the examples of this assignee's U.S. Pat. No. 7,597,825 (hereby incorporated by reference in its entirety) on singlet oxygen generation from the following photosensitizers: protoporphyrin IX; riboflavin; retinol; ADMHP; and melanin after UV light exposure (355 nm). The hypothesis is that the compound of Formula (II) and the alkoxy crylene photostabilizers disclosed in the examples of this assignee's U.S. Pat. No. 7,597,825 act as excited state quenchers for porphyrin compounds and subsequently should prevent or significantly reduce singlet oxygen formation when the porphyrin compounds are exposed to light.

UV and visible light absorption spectra were recorded to investigate to what extent the stabilizers itself absorb UV light. FIG. 1 reveals that the stabilizers are strong UV absorbers with large extinction coefficients (molar absorptivity) of 16,200 M-1 cm-1 (RX-13949; λrnax=334 nm) and 13,200 M-1 cm-1 (SolaStayS1; λmax=336 nm). The compound with the oxygen bridge (Formula IIbi) caused a bathocromic shift of the UV absorption of the lowest energy band. The compound with the sulfur bridge (Formula IIfi) shifted the lowest energy band further into the visible region.

Because of the strong absorption of the two compounds at 355 nm, the initially selected excitation wavelength for the sensitizers for the planned singlet oxygen experiments, the stabilizers would compete for the excitation photons of the excited porphyrin compound. This would lead to a reduced singlet oxygen generation from the sensitizers, but not by excited state quenching of the sensitizers by the stabilizers. To perform meaningful experiments, the sensitizer needs to be excited at a wavelength where the two compounds do not absorb. Protoporphyrin IX has weak absorption bands above 450 nm, where the two compounds are transparent (FIG. 2).

Photoexcitation in these absorption bands generates singlet excited states which deactivate to the ground state or intersystem cross to the triplet state. The two compounds could target the singlet excited states and/or the triplet states. Fluorescence lifetime measurements are a convenient way to measure singlet state quenching by the stabilizers (see this assignee's U.S. Pat. No. 7,776,614). Protoporphyrin IX decay traces were recorded in the absence and presence of difference of the two compounds (FIG. 3). The experiments show that the compound of Formula IIai significantly quenches the protoporphyrin IX fluorescence (reduces fluorescence lifetime; FIG. 3). However, the alkoxy crylene compound of U.S. Pat. No. 7,597,825 caused no reduction in fluorescence lifetime, even at high concentrations, such as 0.1 M (FIG. 3).

Data, such as the collected data shown in FIG. 3, were used to determine the bimolecular quenching rate constant for singlet excited state quenching by alkoxy crylene and compounds IIai, IIbi, IIci, a mixture of IIdi and IIei, and IIfi. The quenching rate constant can be directly extracted from the slope of the plot of the inverse fluorescence lifetime vs. the concentration of the two compounds (FIG. 4). The data reveal a high quenching rate constant with the compound of Formula IIai, IIbi, IIci, and the mixture of IIdi and IIei (close to the diffusion limit) but no observable quenching with the alkoxy crylene compound.

To investigate if triplet states of protoporphyrin IX are quenched, laser flash photolysis experiments were performed. In these experiments, a deoxygenated acetonitrile solution of protoporphyrin IX is excited with short laser pulses from a Nd-YAG laser (355 nm, 5 ns pulse width). Difference absorption kinetic traces were recorded at different observation wavelength (300 to 800 nm) and from these a transient absorption spectrum was constructed (FIG. 5a ). This difference spectrum shows ground state depletion at 400 nm (where protoporphyrin IX absorbs strongly; see FIG. 2). In addition, two bands are observed at 320 and 440 nm, which are assigned to the triplet-triplet absorption of protoporphyrin IX. The triplet absorption decayed with a lifetime of 52 μs with subsequent recovery of the ground state absorption (FIGS. 5b and c , respectively).

The triplet absorption kinetics at 440 nm can be utilized to obtain triplet quenching rate constants by the stabilizers. Triplet decay traces at 440 nm were recorded in the presence of different amounts of alkoxy crylene, Formula IIai, IIbi, IIci, a mixture of IIdi and IIei, and IIfi. The decay traces were fitted to a first-order kinetics. The plot of these pseudo-first-order rate constants (inverse decay lifetime) vs. the concentration of the two compounds gives directly the bimolecular triplet quenching rate constant from the slope (FIG. 6).

The triplet quenching rate constant for Formula IIai is three orders of magnitude smaller than singlet excited state quenching by the compound of Formula IIai. However, since the triplet lifetime (52 μs) is more than three orders of magnitude larger than the singlet excited state lifetime (13 ns), the smaller rate constant for triplet quenching is compensated by the longer triplet lifetime. This makes protoporphyrin IX triplet state quenching by the compound of Formula IIai more efficient than singlet excited state quenching. Similar to the fluorescence quenching experiments, no triplet quenching was observed by the alkoxy crylene compound. Similarly, the triplet excited state quenching of PPIX varies over three orders of magnitude for Formula IIbi, IIci, a mixture of IIdi and IIei, and IIfi. Interestingly, Formula IIci was the most efficient quencher—the PPIX triplet state quenching is almost as fast as the singlet state quenching.

Because Formula IIci contains a ketone functionality, intersystem crossing into the triplet state could be promoted after photoexcitation due to spin-orbit coupling. Stabilizer triplet states could generate singlet oxygen. Low-temperature luminescence experiments in a ethanol matrix. at 77 K were performed in search for phosphorescence of potential triplet states. Only a very weak luminescence was observed with maximum at 492 nm and a quantum yield of less than 1%. Because the excitation spectrum of this luminescence did not match the absorption spectrum, it can be concluded that this luminescence is probably caused by an impurity and no long-lived triplet states of Formula IIci are formed.

The biomolecular quenching rate constants for singlet excited state (k_(q) ^(S)) and triplet excited state (k_(q) ^(T)) quenching of PPIX by stabilizers in acetonitrile solutions at room temperature is shown in Table 1, as well and the Stern-Volmer rate constants (discussed in more detail below).

TABLE 1 Singlet Quenching Triplet Quenching Stern-Volmer Formula k_(q) ^(S) (10⁹ M¹S¹) k_(q) ^(T) (10⁹ M¹S¹) Constant (M¹) IIai 5.3 ± 0.2 0.0061 ± 0.0004 30 IIbi  3.7 ±· 0.4 0.14 ± 0.01 27 IIci 5.2 ± 0.2 3.2 ± 0.  240 IIdi, IIei mixture 4.5 ± 0.2 0.25 ± 0.2  31 IIfi 0.65 ± 0.05 0.0012 ± 0.0001 1.2 Alkoxy Crylene no observable quenching no observable quenching 0.2

The quenching mechanism of protoporphyrin IX singlet excited states and triplet states by the compound of Formula (II) is not clear. A simple energy transfer mechanism would depend on the singlet and triplet energies of the compound of Formula (II) and protoporphyrin IX. To obtain information on excited state energies of the stabilizer, luminescence experiments were performed. The compound of Formula IIai in ethanol solution did not give detectable fluorescence at room temperature. However, weak luminescence was observed of the compound of Formula IIai in a frozen ethanol matrix at 77 K. The luminescence with maximum at 575 nm (FIG. 7c ) originates from the compound of Formula IIai, because the luminescence excitation spectrum (FIG. 7b ) matches well the absorption spectrum of the compound of Formula IIai (FIG. 5a ). The luminescence lifetime could not be determined, because of the weak signal intensity. However, attempts to record time resolved luminescence spectra suggests that the lifetime is shorter than the microsecond time scale. This suggests that the luminescence at 575 nm is not a typical phosphorescence and probably is the fluorescence. If the luminescence at 575 nm is the fluorescence, then the Stoke's shift is unusually large. Independent of the assignment of the luminescence to the fluorescence or phosphorescence, this excited state energy is higher than singlet and triplet energies of protoporphyrin IX and rules out a simple energy transfer quenching mechanism. Another possible quenching mechanism is electron transfer quenching which would depend on the redox potentials of the protoporphyrin and the two quencher compounds.

Singlet oxygen quenching by the compound of Formula (II) is another possible photoprotection mechanism. A convenient way to generate singlet oxygen is by photoexcitation of tetraphenylporphyrin (TPP) in the presence of dissolved oxygen. FIG. 8 shows a typical singlet oxygen phosphorescence spectrum (FIG. 8a ) and its decay trace (FIG. 8b ). The solvent CC1₄ was selected, because it is known that the singlet oxygen has a long lifetime in this solvent (ms time scale), which makes the measurement of quenching kinetics easier. Singlet oxygen phosphorescence decay traces, such as shown in FIG. 8b , were recorded in the presence of different quencher concentrations. After fitting the decay traces to a first-order kinetic model, the bimolecular quenching constants were determined from the plots shown in FIG. 9. The singlet oxygen quenching rate constants of both compounds are relatively low. The slightly higher rate constant for the alkoxy crylene compound is consistent with the additional substituents compared to the compound of Formula IIai.

Finally, an example of the originally planned experiment was performed, where singlet oxygen was generated by pulsed laser excitation in the UV (355 nm) by protoporphyrin IX. Protoporphyrin IX was selected on the basis of its high extinction coefficient (FIG. 2). The solvent DMSO-d₆ was selected because of good solubility of the sensitizer and stabilizers. The deuterated form of DMSO was used because of the longer singlet oxygen lifetime in deuterated solvents compared to solvents containing hydrogen. FIGS. 10 and 11 show kinetic traces of singlet oxygen phosphorescence generated from photoexcitation of protoporphyrin IX. In the presence of small amounts (250 μM) of the compound of Formula IIai (FIG. 10) or the alkoxy crylene compound (FIG. 11) there was significantly reduced singlet oxygen phosphorescence. However, the reduced amount of generated singlet oxygen in the presence of the alkoxy cylene compound is probably caused by competitive excitation light absorption, where most of the light is absorbed by the compound of Formula IIai or the two compounds and not by protoporphyrin IX. Excited state quenching of the protoporphyrin IX by the two compounds is unlikely to occur at these low stabilizer concentrations (p M). As shown in FIGS. 4 and 6, much higher stabilizer concentrations are needed (mM) for excited sensitizer state quenching of porphyrin compounds (sensitizers).

To investigate to what extent the stabilizers can generate singlet oxygen upon direct UV photolysis, singlet oxygen phosphorescence measurements were performed under photolysis at 355 nm. For these experiments CC1₄ was selected as solvent, because of the long lifetime of singlet oxygen in this solvent, which makes these experiments easier to perform: Weak singlet oxygen signals were observed upon photolysis at 355 nm (FIG. 12). Using benzophenone as reference (quantum yield of singlet oxygen generation: 0.35) the low quantum yields of singlet oxygen generation were estimated: compound of Formula IIai: 0.015 and alkoxy crylene: ˜0.001.

To ensure that the observed weak singlet oxygen signals truly originated from the two compounds and not from possible impurities in the sample or solvent, singlet oxygen phosphorescence excitation spectra were recorded. Because the excitation spectrum resembles the absorption spectrum (FIG. 13), it can be concluded that the major amount of observed weak singlet oxygen phosphorescence was generated from the compound of Formula (II). However, no match of the excitation spectrum with the absorption spectrum was observed for the alkoxy crylene compound, which suggests that the observed very weak singlet oxygen originated mostly from impurities.

In conclusion, the mechanism of photoprotection by the compound of Formula (II) and the non-fused alkoxy crylene compound is probably dominated by their strong light absorption and fast deactivation to the ground state. However, excited state quenching, as shown for protoporphyn IX with the compound of Formula IIai, should provide additional photoprotection.

In the previous experiments, singlet oxygen was generated by pulsed laser excitation in the UV spectral region (355 nm) of protoporphyrory IX. The singlet oxygen generation was mostly suppressed by addition of small amounts of the compound of Formula IIai or the alkoxy crylene compound (FIGS. 14a and 14c ). This was explained by a simple optical screening mechanism, where the compound of Formula IIai and alkoxy crylene absorb the UV light.

In the new experiments, laser excitation was performed with visible light at 532 nm, where the compound of Formula IIai and the alkoxy crylene compound are transparent. No suppression of singlet oxygen generation was observed by the presence of the alkoxy crylene compound even at high concentrations (37 mM) (FIG. 1d ). The absence of singlet oxygen suppression with 532 nm excitation supports the optical screening mechanism with 355 nm excitation. In the presence of the compound of Formula IIai at concentrations above 3 mM the. amount of generated singlet oxygen was reduced (FIG. 14b ). This reduction is probably caused by protoporphyrin IX excited state quenching by the compound of Formula IIai. In the previous experiments it was shown that protoporphyrin IX singlet and triplet excited states are quenched by the compound of Formula IIai, but not by the alkoxy crylene compound.

The above-described experiments with protoporphyrin IX were performed in DMSO-d₆, a solvent with a relatively short singlet oxygen lifetime, because the polar protoporphyrin IX is not soluble enough is solvents with long singlet oxygen lifetimes, such as CDC1₃ and CC1₄. Solvents with long singlet oxygen lifetimes make singlet oxygen phosphorescence measurements significantly easier to perform.

Singlet oxygen phosphorescence experiments were performed to investigate if the large differences in triplet quenching rate constants have an impact on the observed singlet oxygen yields. The dimethyl ester derivative of PPIX (MePPIX, FIG. 15) was selected as sensitizer, because of better solubility in a solvent with long singlet oxygen lifetime (CDC1₃). The excited state properties of protoporphyrin IX should not be effected by the methyl ester functionality. Air saturated CDC1₃ of MePPIX were excited with a pulsed Nd-YAG laser with visible light at 532 nm, where the stabilizers are mostly transparent. FIG. 16 shows the generated kinetic traces of singlet oxygen phosphorescence in the absence and presence of stabilizers. Comparison of these kinetic traces shows major differences for the different stabilizers. The non-bridged stabilizer, alkoxy crylene did not suppress singlet oxygen generation. The lack of singlet oxygen suppression is consistent with the lack of observable quenching of singlet or triplet excited states of PPIX by alkoxy crylene. The bridged stabilizers suppressed singlet oxygen generation to different degrees with IIci showing the largest suppression.

The singlet oxygen phosphorescence experiments shown in FIG. 3 using the dimethyl ester derivative of protoporphyrin IX in CDC1₃ are qualitatively similar to those shown in FIG. 14 using protopophyrin IX in DMSO-d₆. Although singlet oxygen phosphorescence detection was easier in CDC1₃, decomposition of protoporphyrin IX dimethyl ester by singlet oxygen caused a larger error in phosphorescence intensity, which was especially visible in FIG. 16d compared to FIG. 14d . The longer singlet oxygen lifetime in CDC1₃ makes the chromophore more sensitive to oxidative damage.

To demonstrate that the suppression of singlet oxygen generation from photoexcitation at 532 nm is caused by singlet excited state quenching of protoporphyrin IX by the compound of Formula (II), Stern-Volmer analysis of the data in FIG. 14b and FIG. 16 was performed. The singlet oxygen phosphorescence intensity in the absence of stabilizer (i.e., the compound of Formulae IIai, IIbi, IIci, a mixture of IIdi and IIei, or IIfi) (I₀) divided by the singlet oxygen phosphorescence intensity in the presence of stabilizer (i.e., the compound of Formulae IIai, IIbi, IIci, the mixture of IIdi and IIei, or IIfi) (I) was plotted against the Formula (II) concentration (FIG. 17). From the slope of these plots (Stern-Volmer constant) and the lifetime of the quenched excited state, the bimolecular quenching constant can be extracted. If the excited state, which is quenched by the compound of Formula IIai (which causes a reduction in singlet oxygen production) is the singlet excited state of protoporphyrin IX then, using the previously measured fluorescence lifetime in acetonitrile (if =12.7 ns) a quenching rate constant of 2.4×10⁹ M⁻¹s⁻¹ is estimated. This rate constant is in the same order of the previously measured rate constant using fluorescence quenching (5.3×10⁹ M⁻¹s⁻) which indicates that singlet excited state quenching of protoporphyrin by the compound of Formula IIai is predominantly causing the suppression of singlet oxygen generation. The rate constant derived from singlet oxygen phosphorescence quenching (FIG. 17) is only half of the more directly derived rate constant from fluorescence quenching, which could be caused by the difference in solvents or by some contribution of protoporphyrin triplet quenching by the compound of Formula IIai. If the suppression of singlet oxygen generation would be entirely caused by triplet protoporphyrin IX quenching by the compound of Formula IIai, the rate constant from the Stern-Volmer plot (FIG. 4) would be ˜3×10⁷ M⁻¹s⁻¹ considering a protoporphyrin IX triplet lifetime of ˜1 μs in air saturated DMSO. This rate constant is 5 times higher than the directly measured rate constant by laser flash photolysis (6.1×10⁶ M⁻¹s⁻¹. This suggests that protoporphyrin IX triplet quenching by the compound of Formula (II) makes only a minor contribution to the suppression of singlet oxygen generation under these conditions. It must be noted that protoporphyrin IX triplet lifetime of ˜1 μs in air saturated DMSO was only estimated based on the directly measured triplet lifetime in air saturated acetonitrile and considering the different oxygen concentration in DMSO compared to acetonitrile. If necessary, the protoporphyrin IX triplet lifetime in air saturated DMSO can easily be measured by laser flash photolysis.

The Stern-Volmer constants are in direct correlation with the singlet oxygen suppression efficiency. Table 1 (above) summarizes the Stern-Volmer constants and PPIX singlet and triplet state quenching rate constants. Three different ranges of Stern-Volmer constants were observed. For alkoxy crylene and compound IIfi, only negligible singlet oxygen suppression and low Stern-Volmer constants were observed, which is probably caused by the low PPIX singlet and triplet quenching rate constants of these stabilizers. For compounds IIai, IIbi, and the mixture of IIdi and IIei, Stern-Volmer constants of about 30 M⁻¹ were observed. For these three stabilizers, high PPIX singlet quenching rate constants (about 5×10⁹ M⁻¹s⁻¹) but low triplet quenching rate constants (<10⁹ M⁻¹s⁻¹) were observed. Here, the singlet oxygen suppression is probably dominated by PPIX singlet excited state quenching by these stabilizers. The highest Stern-Volmer constant was observed for compound IIci (240 M⁻¹). Because of the very high PPIX triplet quenching rate constant by compound IIci (3.2×10⁹ M⁻¹s⁻¹), the singlet oxygen suppression is probably dominated by triplet quenching. To prove this switch in mechanism and kinetic control of singlet oxygen suppression, additional kinetic parameters would need to be determined, which are easily accessible by laser flash photolysis and time correlated single photon counting. These kinetic parameters include the MePPIX triplet and singlet lifetimes in air saturated and oxygen free CDC1₃ and the bimolecular quenching constant by oxygen.

The complex quenching reaction mechanism of protoporhyrin IX excited states is summarized in Scheme 1.

Additional conjugated fused tricyclic compounds having electron withdrawing groups having Formulas IIai, IIbi, IIci, IIdi, and IIei were tested against the alkoxy crylene compound as shown in FIGS. 18 and 19.

The redox potential of protoporphyrin IX, Formula IIai, IIbi, IIci, a mixture of IIdi and IIei, IIfi, and alkoxy crylene were determined with respect to a Ag/AgC1 reference electrode. For these experiments, dimethylsulfoxide (DMSO) and tetrabutylammonium perchlorate (TBAP) were obtained from Sigma Aldrich and used as received. Acetone was obtained from Fisher Scientific. Solutions of 0.01 M (10 mM) of protoporphyrin IX, Formula IIai, IIbi, IIci, a mixture of IIdi and IIei, IIfi, and alkoxy crylene were prepared by dissolving measured amounts in a supporting electrolyte of 0.1 M TBAP in DMSO; the total volume of each sample solution was 15 mL. Platinum wires (BASi MW-1032) of diameter 0.5 mm were employed for both the working electrode (WE) and counter electrode (CE). A dry-solvent tolerant Ag/AgC1 reference electrode (RE) was obtained from eDAQ (Model ET072). The WE and CE were cleaned prior to each by first rinsing in acetone, then DI, followed by soaking in ˜50% aqueous H₂SO₄ for 10-20 minutes and then a final DI rinse. The RE electrode was cleaned prior to each use by an acetone rinse followed by DI rinse. Each sample solution was prepared in a fresh glass vial which had been rinsed with DI then acetone and allowed to dry. Immediately after preparing each solution, it was purged with pure N₂ gas for 15-20 minutes with the electrodes in place. Voltammetry data was collected shortly afterwards with an EG&G PAR 263 A Potentiostant/Galvanostat operated using a Labview-based control program. Scans were performed at various potential ranges between +2.0V and −2.0V (vs Ag/AgC1); all scan rates were constant at 200 mV/s.

The voltammograms for protoporphyrin IX appear to show the presence of two distinct redox couples (FIG. 19a ). The first redox couple has a large reduction peak at −1255 mV and a smaller oxidation peak at −610 mV (two much smaller oxidation peaks are present at −202 mV and +164 mV which may also be associated with this couple); the redox potential for this couple is thus estimated as −932 mV. The second redox couple has a reduction peak near −1741 mV and an oxidation peak near −1152 mV; this yields a redox potential of approximately −1446 mV.

The voltammograms for Formula IIai also show the presence of two distinct redox couples (FIG. 19b ). The first redox couple has a reduction peak at −757 mV and an oxidation peak at −560 mV; the redox potential for this couple is thus estimated as −658 mV. The second redox couple has a reduction peak at −1297 mV and an oxidation peak at −1102 mV; the redox potential is approximately −1199 mV.

The voltammograms for Formula IIbi show the presence of two distinct redox couples (FIG. 19c ). The first redox couple has a reduction peak at −864 mV and an oxidation peak at −706 mV; the redox potential for this couple is thus estimated as −785 mV. The second redox couple has a reduction peak at −1537 mV and oxidation peaks at −1466 mV (small) and +430 mV (large); the redox potential is estimated as −1501 mV.

The voltammograms for Formula IIfi show the presence of two distinct redox couples (FIG. 19d ). The first redox couple has a reduction peak at −969 mV and an oxidation peak at −782 mV; the redox potential for this couple is thus estimated as −875 mV. The second redox couple has a reduction peak at −1409 mV and oxidation peaks at −1286 mV (small) and +434 mV (large); the redox potential is estimated as −1347 mV.

The voltammogram for Formula IIci shows the presence of only one distinct redox couple (FIG. 19e ). This couple has a reduction peak at −656 mV and an oxidation peak at −300 mV; the redox potential is thus estimated as −493 mV.

The voltammogram for the mixture of Formula IIdi and Formula IIei also shows the presence of only one distinct redox couple (FIG. 19f ). This couple has a reduction peak at −545 mV and an oxidation peak at +54 mV; the redox potential for this couple is thus estimated as −245 mV.

The voltammograms for alkoxy crylene show the presence of two distinct redox couples (FIG. 19g ). The first redox couple has a reduction peak at −1183 mV and an oxidation peak at −1038 mV; the redox potential for this couple is thus estimated as −1110 mV. The second redox couple has a reduction peak at −1751 mV and an oxidation peak at +318 mV; the redox potential is estimated as −694 mV. 

1. (canceled)
 2. A method of suppressing the generation of a reactive oxygen species selected from the group consisting of singlet oxygen, superoxide anion, peroxide, hydroxyl radical, hydroxyl ion, and mixtures thereof, by an excited pigment when mammalian endogenous pigment is exposed to light, thereby exciting the pigment to an excited state, by quenching the excited state of the pigment compound with a conjugated fused tricyclic compound having electron withdrawing groups of Formula (II) or a salt thereof:

wherein: A is selected from the group consisting of O, S, C═O, C═S,

B¹, B², D¹, and D² are each independently selected from the group consisting of F, Cl, Br, I, CF₃, CCl₃, NR³ ₃ ⁺, NO₂, CN, C(═O)R⁴, C(═O)OR¹, SO₂R⁵, aryl, and —C═CHR⁶; each m independently is 0, 1, 2, 3, or 4; n is 0 or 1; each R¹ is independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl; R² is selected from the group consisting of H, alkyl, cycloalkyl, alkenyl, alkynyl, and aryl; each R³ is independently selected from the group consisting of H and C₁-C₆ alkyl; each R⁴ is independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl; each R⁵ is independently selected from the group consisting of H, O—, OH, NH₂, and Cl; and, each R⁶ is independently selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl.
 3. A method of protecting skin from oxidative stress caused by the photogeneration of a reactive oxygen species from the group consisting of singlet oxygen, superoxide anion, peroxide, hydroxyl radical, hydroxyl ion, and mixtures thereof, comprising coating the skin with a pigment excited state quencher capable of accepting or donating an electron from or to a pigment compound in the excited state and returning the excited pigment compound to its ground state, said pigment quencher comprising a conjugated fused tricyclic compound having electron withdrawing groups of Formula (II) or a salt thereof:

wherein: A is selected from the group consisting of O, S, C═O, C═S,

B¹, B², D¹, and D² are each independently selected from the group consisting of F, Cl, Br, I, CF₃, CCl₃, NR³ ₃ ⁺, NO₂, CN, C(═O)R⁴, C(═O)OR¹, SO₂R⁵, aryl, and —C═CHR⁶; each m independently is 0, 1, 2, 3, or 4; n is 0 or 1; each R¹ is independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl; R² is selected from the group consisting of H, alkyl, cycloalkyl, alkenyl, alkynyl, and aryl; each R³ is independently selected from the group consisting of H and C₁-C₆ alkyl; each R⁴ is independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl; each R⁵ is independently selected from the group consisting of H, O—, OH, NH₂, and Cl; and, each R⁶ is independently selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl.
 4. A method of protecting healthy cells adjacent to cancerous or pre-cancerous cells undergoing photodynamic therapy comprising applying a composition comprising a pigment excited state quencher compound to said adjacent cells to reduce the generation of reactive oxygen species from said healthy cells while the photodynamic therapy generates free radical oxygen from said cancerous or pre-cancerous cells, with a conjugated fused tricyclic compound having electron withdrawing groups of Formula (II) or a salt thereof:

wherein: A is selected from the group consisting of O, S, C═O, C═S,

B¹, B², D¹, and D² are each independently selected from the group consisting of F, Cl, Br, I, CF₃, CCl₃, NR³ ₃ ⁺, NO₂, CN, C(═O)R⁴, C(═O)OR, SO₂R⁵, aryl, and —C═CHR⁶; each m independently is 0, 1, 2, 3, or 4; n is 0 or 1; each R¹ is independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl; R² is selected from the group consisting of H, alkyl, cycloalkyl, alkenyl, alkynyl, and aryl; each R³ is independently selected from the group consisting of H and C₁-C₆ alkyl; each R⁴ is independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl; each R⁵ is independently selected from the group consisting of H, O—, OH, NH₂, and Cl; and, each R⁶ is independently selected from the group consisting of alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl. 5-26. (canceled)
 27. A cosmetic or dermatological composition for coating a skin surface to protect the skin from getting damaging amounts of photogenerated reactive oxygen species when skin cell-contained or blood-contained pigments are exposed to sunlight, or other visible light comprising a cosmetically acceptable carrier, and a compound of Formula IIb, IIc, IId, IIe, IIf, IIg, IIh, IIi, IIj, IIk, IIl, IIm, IIn or a combination thereof:

and mixtures thereof, wherein: each R¹ is independently selected from the group consisting of H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and aryl; and, R² is selected from the group consisting of H, alkyl, cycloalkyl, alkenyl, alkynyl, and aryl.
 28. The cosmetic or dermatological composition of claim 27, wherein the compound of Formula IIb, IIc, IId, IIe, IIf, IIg, IIh, IIi, IIk, IIl, IIm, IIn, or a combination thereof, is present in an amount of about 0.01% by weight to about 20% by weight, based on the total weight of the composition.
 29. The cosmetic or dermatological composition of claim 27 further comprising an additional photoactive compound selected from the group consisting of p-aminobenzoic acid and salts and derivatives thereof; anthranilate and derivatives thereof; salicylate and derivatives thereof; cinnamic acid and derivatives thereof; dihydroxycinnamic acid and derivatives thereof; camphor and salts and derivatives thereof; trihydroxycinnamic acid and derivatives thereof; dibenzalacetone naptholsulfonate and salts and derivatives thereof; benzalacetophenone naphtholsulfonate and salts and derivatives thereof; dihydroxy-naphthoic acid and salts thereof; o-hydroxydiphenyldisulfonate and salts and derivatives thereof; p-hydroxdydiphenyldisulfonate and salts and derivatives thereof; coumarin and derivatives thereof; diazole derivatives; quinine derivatives and salts thereof; quinoline derivatives; hydroxyl-substituted benzophenone derivatives; naphthalate derivatives; methoxy-substituted benzophenone derivatives; uric acid derivatives; vilouric acid derivatives; tannic acid and derivatives thereof; hydroquinone; benzophenone derivatives; 1, 3, 5-triazine derivatives; phenyldibenzimidazole tetrasulfonate and salts and derivatives thereof; terephthalyidene dicamphor sulfonic acid and salts and derivatives thereof; methylene bis-benzotriazolyl tetramethylbutylphenol and salts and derivatives thereof; bis-ethylhexyloxyphenol methoxyphenyl triazine and salts, diethylamino hydroxyl benzoyl and derivatives thereof; and combinations of the foregoing. 30-70. (canceled) 